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May 14, 2019, 04:44 PM
Chino Renegade oh-gee, yo
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Super Tigre carb tuning FAQ


Use low nitro fuel (5% is best IMO) and a hot glow plug with a long reach like he McCoy MC59. Adjust the idle needle for a slow reliable idle and the high speed needle for about 400-500rpm rich from peak. If the midrange is rich as is sometimes common with SuperTigre/Como Engines, you adjust the spraybar which is the two little screws on the side of the carb that holds the spraybar in. Adjust the spraybar in roughly ‘1-hour’ increments aiming the fuel inlet lower towards the engine mount. It is always best to start out with the spraybar “straight in”; with the carburetor removed from the engine, looking into the bottom of the carb, the “cats eye” should be visible and centered in the bore.

Many times, the fuel nipple will basically end up aiming at the rear mounting hole. Often I’ve found this is necessary until the engine has a couple gallons of fuel through it. It is not necessary to program the transmitter to open the throttle slower. Setting the carb properly will 99% of be time cure any midrange issues you may have. Setting a SuperTigre/Como carburetor like conventional 2-needle carburetors will likely make the idle/midrange lean because you are trying to make the idle needle do the work of the idle mixture and midrange (when the midrange is likely rich) and that isn’t how the carburetor is designed to be setup.
A rich engine will blubber and clear out usually (unless way too rich), a lean engine will hesitate or cut out. At least how I see it and have experienced it. I’ve had and still have numerous ST engines and with the carburetor setup properly, they will not hesitate or cutout. Many ST engines run rich in the midrange and guys try tuning that midrange leaner by leaning the low speed needle. This will make the idle too lean and usually will cause flameouts. Many guys dump ST carbs because they don’t understand how to set them up. There is two ways to set them, and both work well. Both methods involve adjusting the spraybar position to adjust midrange mixture density if the factory spraybar position is too rich. Rarely the midrange is lean and is rarely if ever an issue with the MAG type carbs. The midrange mixture absolutely 100% will affect acceleration from idle to WOT without question. Of course a poorly tuned high speed and low speed needle settings will cause problems too.
And my take is OS 8 plugs aren’t hot enough for ST engines. The shorter reach doesn’t help either. If this fellow wants to try a good plug for these engines, I’ll mail him one free of charge. I have a spare MC59 brand new. They’re great plugs.
Last edited by Wrench66; May 14, 2019 at 04:52 PM.
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